Today, the name Rohanský Island is used for part of the territory of Karlín, and as a matter of fact, is no longer an island. The original island was built in 1550 with the use of river deposition by a Prague miller Jan Šašek. At the turn of the 19th and 20th centuries, it was connected with the Jerusalem Island on the west side. In 20s of the 20th century it was connected with the Libeň Island and the Karlín riverbank and thus lost the characteristics of an island and became a waterfront.
Today’s name of the island is derived from the name of the Prague counselor and master carpenter Joseph Rohan, who was one of the owners of the island. Originally, it was called after its creator Šaškovský. In the 17th and 18th centuries it was used by the Old Town Hall and was therefore also called the Old Town Island. After it was connected to the Jerusalem Island, the western part of the island was called Jerusalem and the eastern part the Rohan Island. Between 1777 – 1870, Gabriela Rottenhan – the wife of Prague's highest aristocrats Count Henry was the owner of the island and it was called Rottenhanský. In the years 1850 - 1875 it was called after its next owner, the Prague citizen John George Köpple.